title: K+ channel openers suppress myotonic activity of human skeletal muscle in vitro.
abstract: Isolated fibre bundles from myotonic human skeletal muscle showed after-contractions and spontaneous mechanical activity. The K+ channel openers cromakalim (10-100 mumols/l) and EMD 52962 (1-10 mumols/l) completely suppressed these abnormalities in mechanical activity. Voltage-clamp experiments revealed that cromakalim (100 mumols/l) increased the membrane K+ conductance of isolated, non-myotonic human skeletal muscle fibres 4-fold; Cl- conductance was not altered. The data show that myotonia is suppressed by an increase in in membrane K+ conductance.
authors.affiliation: Physiologisches Institut, Universität München, F.R.G.
authors.forename: S
authors.initials: S
authors.lastname: Quasthoff
authors.forename: A
authors.initials: A
authors.lastname: Spuler
authors.forename: W
authors.initials: W
authors.lastname: Spittelmeister
authors.forename: F
authors.initials: F
authors.lastname: Lehmann-Horn
authors.forename: P
authors.initials: P
authors.lastname: Grafe
mesh_terms: D001578:Benzopyrans / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D019806:Cromakalim; D004095:Dihydropyridines / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008839:Microelectrodes; D009119:Muscle Contraction / Q000187:drug effects; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D015221:Potassium Channels / Q000187:drug effects*; D011758:Pyrroles / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D001578:Benzopyrans; D004095:Dihydropyridines; D015221:Potassium Channels; D011758:Pyrroles; D014665:Vasodilator Agents; D019806:Cromakalim; C061050:bimakalim